Add some integration tests to open-source project

The open-source ImageResizer project has 5 plugins that need to upgrade to automated tests. These plugins are simple data access wrappers for Azure Blob Storage, Amazon S3, MongoDB GridFS, Microsoft SQL, and a generic HTTP provider. (The exact names are AzureReader2, S3Reader2, MongoReader, S3Reader, and RemoteReader). Each has a doc page under [login to view URL] The .FileExists(path, query), .GetFile(path,query) and [login to view URL]() methods exposed by each plugin class should be tested. Missing blobs and containers should produce a FileNotFoundException. RemoteReader and S3Reader will need to be tested against live servers (we have some). AzureReader2, SQLReader, and MongoReader can use local instances. Setup and teardown of local mongo/sql/azure instances and processes will need to be automated (this is pretty well documented on the web). The final test sequence will need to run both locally and on an AppVeyor server. You can get a free AppVeyor account and add your fork in seconds. For fast testing, replace the [login to view URL] file with a trimmed solution including only the projects and tests you're using. Fork the appveyor branch for your work: [login to view URL] Our refactored providers can be found on the vpp-simplify branch, but until we have integration tests we can't merge them into the mainline: [login to view URL]